Abstract: In considering phenomenal substance, an empiricist notion of ‘phenomenon’ as the manifest is to be distinguished from a rationalist notion of phenomenon as the non-fundamental. And the pure concept of substance as subject is to be distinguished from the schematized concept of substance as enduring. The notion of phaenomenon substantiatum in Leibniz, Baumgarten, and early Kant is that of a non-substance that is treated as a substance, e.g. a property treated as a subject of properties, whether in metaphor (‘love is blind’) or metaphysics. Body and matter were prime examples of such ‘merely comparative’ subjects, monads being the true fundamental substances. Phenomenal substance in later Kant is a species of phaenomenon substantiatum, constituted by relational properties of attraction and impenetrability; it is a non-substance that serves as substance because it endures.

Keywords: attraction, Baumgarten, enduring, impenetrability, Kant, Leibniz, monads, phaenomenon substantiatum, phenomenal substance, phenomenon, pure concept, schematized concept, substance,